7-mercapto-7-deoxylincomycins and process for preparing the same

ABSTRACT

WHICH ON ACYLATION YIELDS COMPOUNDS OF FORMULA I.   HYDROPYRAN   2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-SH)-CH(-NH2)-)TETRA-   AND HEATING IT WITH HYDROGEN SULFIDE IN AN INERT SOLVENT FOR FORM A COMPOUND OF THE FORMULA:   PYRAN   2-(R-S-),3,4,5-TRI(HO-),6-((-CH(-CH3)-NH-)&gt;CH-)TETRAHYDRO-   AN INERT SOLVENT IN THE PRESENCE OF AN ACID ACCEPTOR, THE 2-, 3-, AND 4-HYDROXY GROUP MAY BE COVERSED WITH PROTECTIVE GROUPS, TO FORM A NOVEL COMPOUND OF THE FORMULA:   HYDROPYRAN   2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-HALO)-CH(-NH2)-)TETRA-   ARE PREPARED BY HEATING A COMPOUND OF THE FORMULA:   TETRAHYDROPYRAN   2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-SH)-CH(-NH-CO-R4)-)   ANTIBACTERIAL COMPOUNDS OF THE FORMULA:

United States Patent 3 689 474 7-MERCAPTO-7-DEbXSILINCOMYCINS AND PROCESS FOR PREPARING THE SAME Fred Kagan, Kalamazoo, and Barney J. Magerlein, Portage, Mich., assignors to The Upjohn Company, Kalamazoo, Mich.

No Drawing. Continuation-impart of application Ser. No. 725,531, Apr. 30, 1968. This application Aug. 4, 1970, Ser. No. 60,929

Int. Cl. C07g 11/00 US. Cl. 260-210 R 11 Claims ABSTRACT OF THE DISCLOSURE Antibacterial compounds of the formula:

7 fl) 3 R4CNH- HO t are prepared by heating a compound of the formula:

CHI

- -Halo NHaan inert solvent in the presence of an acid acceptor, the 2-, 3-, and 4-hydroxy group may be covered with protective groups, to form a novel compound of the formula:

O. 1 l (L SR II III and heating it with hydrogen sulfide in an inert solvent to form a compound of the formula:

which on acylation yields compounds of Formula I.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our copending application Ser. No. 725,531, filed Apr. 30, 1968, now US. Pat. 3,544,551, granted Dec. 1, 1970.

BRIEF SUMMARY OF THE INVENTION ice The novel process of the invention and the novel intermediates produced therein are represented in the following sequence:

-o o 0H 01; IV I R OH H In this process Rv is the radical of a mercaptan,

u R4C- is the acyl moiety of lincomycin and Halo is chlorine, bromine, or iodine. R advantageously is alkyl of not more than 20 carbon atoms, advantageously not more than eight carbon atoms; cycloalkyl of not more than 8 carbon atoms; or aralkyl of not more than 12 carbon atoms.

Any or all of the 2-, 3-, and 4-hydroxy groups as well as the SH group can be esterified or etherified as more particularly described in the parent application.

Examples of alkyl of not more than 20 carbon atoms are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl and the isomeric forms thereof. Examples of cycloalkyl are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, Z-methylcyclopentyl, 2,3- dimethylcyclobutyl, 4-methylcyclobutyl, and S-cyclopentylpropyl. Examples of aralkyl are benzyl, phenethyl, a-phenylpropyl, and a-naphthylmethyl.

When the 7(S)-epimer of Compound H, which has the following formula:

' Halo NHris used as the starting compound, the 7(R)-epimer of Compound III having the following structure.

HO l0 III(R) 3 is obtained. When the 7(R)-epimer of compound II, which has the following formula:

is used as the starting compound, the 7 (S)-epimer of compound III having the following structure CH3 HN v no 1-| SR 011 is obtained.

III(S) OH L l-l H OH 1v s is obtained. When the 7-(S)-epimer of compound III is reacted with hydrogen sulfide, the 7(R)-epimer of compound IV having the formula is obtained.

The starting compounds of Formula II are found in US. Pat. 3,502,648.

DETAIL/ED DESCRIPTION The novel intermediates of Formula III are prepared by dehydrohalogenation of compounds of Formula II. This suitably is effected by heating a compound of Formula H with an acid acceptor in a solvent. Suitable acid acceptors include anhydrous sodium carbonate, potassium carbonate, triethylamine, collidine, and potassium hydroxide. Suitable solvents are dimethylformamide, dimethyl sulfoxide, ethyleneglycol, benzene and alcohol. The temperature can range from about 25 C. to about the boiling point of solvent.

The novel intermediates of Formula III are converted to a compound of Formula IV by heating in an inert solvent under a pressure of hydrogen sulfide. Suitably the compound of Formula HI is mixed with 2-propanol, or like solvent, saturated with hydrogen sulfide and heated in a bomb at a temperature of about 100 C. Higher or lower temperatures, say from about 25 C. to about 150 C., can be used.

The intermediates of Formula III exist either in the protonated or non-protonated forms according to the pH of the environment. When the protouated form is intended, the compound is qualified as an acid-addition salt and when the non-protonated form is intended it is qualified as the free base. The free bases can be converted to stable acid-addition salts by neutralizing the free base with the appropriate acid to below about pH 7.0, and advantageously to about pH 2 to pH 6. Suitable acids for this purpose include hydrochloric, sulfuric, phos-' phoric, thiocyanic, fluosilicic, hexafluoroarsenic, hexafiuorophosphoric, acetic, succini-c, citric, lactic, maleic, fumaric, pamoic, cholic, palmitic, muic, amphoric, glutaric, glycolic, phthalic, tartaric, lauric, stearic, salicylic, 3 phenylsalicylic, 5 phenylsalicylic, 3 methylglutaric, orthosulfobenzoic, cyclopentanepropionic, 1,2 cyclohexanedicarboxylic, 4 cyclohexanecar-boxylic, octadecenylsuccinic, octenylsuccinic, methanesulfonic, benzensulfonic, helianthic, Reineckes, dimethyldithiocarbamic, cyclohexylsulfamic, hexadecylsulfamic, octadecylsulfamic, sorbic, monochloroacetic, undecylenic, 4'-hydroxyazobenzene- 4-sulfonic, octyldecylsulfurie, picric, benzoic, cinnamic, and like acids.

The acid-addition salts can be used for the same purposes as the free base or they can be employed to upgrade the same. For example, the free base can be converted to an insoluble salt, such as the picrate, which can be subjected to purification procedures, for example, solvent extractions and washings, chromatography, fractional liquid-liquid extractions, and crystallization and then used to regenerate the free base form by treatment with alkali or to make a different salt by metathesis. Or the free base can be converted to a water-soluble salt, such as the hydrochloride or sulfate and the aqueous solution of the salt extracted with various water-immiscible solvents before regenerating the free base form by treatment of the thus-extracted acid solution or converted to another salt by metathesis. The free bases of Formula III can be used as a bufier or as an antacid. The compounds of Formula III react with isocyanates to form urethanes and can be used to modify polyurethane resins. The thiocyanic acid addition salt when condensed with formaldehyde forms resinous materials useful as pickling inhibitors according to US. Pats. 2,425,320 and 2,606,155. The free bases also make good vehicles for toxic acids. For example, the fluosilicic acid addition salts are useful as mothproofing agents according to US. Pats. 1,915,334 and 2,075,359 and the hexa-fluoroarsenic acid and hexafluorophosphoric acid addition salts are useful as parasiticides according to US. Pats. 3,122,536 and 3,122,552.

The novel intermediates of Formula III are also useful for preparing 7-mercapto-7-deoxy-a-thiolincosaminides of Formula IV which are described and claimed in the parent application.

The following examples are illustrative of the process and products of the present invention but are not to be construed as limiting. The parts and percentages are by weight and the solvent ratios are by volume unless otherwise specified.

EXAMPLE 1 7 (S)-mercapto 7 deoxylincomycin [methyl 7-mercapto- 6,7,8-trideoxy 6 (trans-l-rnethyl-4-propyl-L-2-pyrrolidinecarboxamido) 1 thio L threo-a-D-galactooctopyranoside] PART A-1 Methyl 6,7(R)-aziridino-7-deoxy-u-thiolincosaminide OH: CH:

HzN- no VIIR OH SMe A mixture of 1 g. of methyl 7(S)-chloro-7-deoxy-athiolincosaminide (Example 1, U.S. Patent 3,502,648) and 3 g. of anhydrous sodium carbonate in 40 ml. of dimethylformamide was heated at reflux for 5 min. The solvent was distilled under vacuum. The residue was crystallized from methanol alfording 370 mg. (45.2% yield) of methyl 6,7(R)-aziridino-7-deoxy-a-thio1incosaminide; M.P. 192-198 C. A second crop of crystals, M.P. 182189, 160 mg. (18.5%), was obtained on concentration of the mother liquors. Two recrystallizations from methanol-acetone gave crystals, M.P. 203-220 C., [u] +320 (dimethyl sulfoxide). On further recrystallization the melting point is increased to 220222 C.

Analysis.Calcd. for C H NO S (percent): C, 45.94; H, 7.28; N, 5.95. Found (percent): C, 45.97; H, 7.44; N, 6.19.

PART B-l Methyl 7 (S) -mercapto-7-dcoxy-a-thiolincosaminide CHI CH3 A mixture of 1.5 g. of methyl 6,7(R)-aziridino-7-deoxy-a-thiolincosaminide in 30 ml. of 2-propanol was saturated with H S while cooling in a bath of ice-methanol. The reaction mixture was heated in a bomb on a steam bath for 5 hours. During this time methyl 6,7- aziridino 7 deoxy-a-thiolincosaminide gradually dissolved forming a solution from which crystalline methyl 7(S)-mercapto-7-deoxy oz thiolincosamim'de began to precipitate. Filtration of the cooled mixture gave 1.6 g. of methyl 7 (8)-mercapto-7-deoxy-a-thiolincosaminide, M.P. 190l97 C. A portion was recrystallized from ethanol to form the analytical sample, M.P. 195198 C.

Analysis.Calcd. for C H -NO S (percent): C, 40.13; H, 7.11; N, 5.20; S, 23.80. Found (percent): C, 40.36; H, 7.12; N, 5.03; S, 24.21.

PART C-l 7(R)-mercapto-7-deoxylincomycin hydrochloride CH3 CH3 g -SH HaN- P HA--NH no no O K L K L OH OH l i Me Me H H vrms) me) To a solution of 5.2 g. (25.2 mM.) of trans-l-methyl- 4-n-propyl-L-proline hydrochloride and 7.16 ml. (51 mM.) of triethylamine in 250 ml. of acetonitrile cooled in an ice-methanol bath was added 3.42 ml. (25.2 mM.) of i-butyl chloroformate. After stirring for 20 minutes, a

solution of 6.8 g. (25.2 mM.) of methyl 7(S)-mercapto- 7-deoxy-a-thiolincosaminide in ml. of water was added. The resulting reaction mixture was stirred at ambient temperature for 2 hrs. The organic solvent was distilled in vacuo and the residue extracted with methylene chloride. After drying the methylene chloride was distilled leaving a residue of 10.2 g. The crude oil was dissolved in 50 ml. of acetone and excess dilute HCl added. An additional 250 ml. of acetone was added causing the precipitation of a gummy solid. This precipitate hardened when triturated with 250 ml. of fresh acetone. It was collected by filtration. A 1 g. portion was chromatographed over silica gel using methanol-chloroform 1:4 for elution. The fractions showing antibacterial activity were pooled and evaporated to dryness. This material (307 mg.) was dissolved in acetone and acidified. Evaporation of the solvent gave 7(S)-mercapto-7-deoxylincomycin hydrochloride as a glassy solid.

Analysis.--Calcd. for C H 'N O S -HCl (percent): C, 47.09; H, 7.69; N, 6.10. Found (percent): C, 47.25; H, 7.87; N, 5.60.

at 20 hours.

EXAMPLE 2 7 (R) -mercapto-7-deoxyllincomycin hydrochloride If" .H.

( i H(K fiflcm PART A-2a 'Methyl 6,7 (S)-aziridino-7-deoxy-a-thiolincosaminide Chlorine (52.5 g.) was passed into a cooled solution of 197.2 g. of t-riphenylphosphine in 1.5 l. of anhydrous acetonitrile. To this solution was added 18.7 g. of methyl a-thiolincosaminide (Example 1 U.S. Patent 3,179,565). The mixture was stirred for 2.5 hrs. at ambient temperature and then 50 ml. of methanol added. The solution was evaporated under vacuum. The residue was dissolved in methylene chloride and washed 3 times with water. The aqueous extract was made alkaline with aqueous sodium hydroxide containing ice and extracted 4 times with methylene chloride. The methylene chloride solution was dried over anhydrous sodium sulfate and evaporated to dryness. The residue was chromatographed over silica gel using chloroform-methanol (4:1) for elution and taking 100 ml. fractions. The efliuent was monitored by TLC (thin layer chromatography) and fractions were combined on this basis. There was obtained 4.4 g. of material which was essentially methyl 7 (S)-chloro-7-deoxy-a-thiolincosaminide and 3.2 g. of a fraction containing this product and a slightly more polar product. This latter fraction when triturated in methanol afforded 2.48 g. of methyl 7(S)- chloro-7-deoxy-u-thiolincosaminide. The methanol solu tion was evaporatedto dryness and the residue rechromatographed over silica gel to give 700 mg. of methyl 6,7(S)-aziridino-7-deoxy oz thiolincosamim'de (slightly more polar than methyl 7(S)-chloro-7-deoxy-a-thiolincosaminide) which on crystallization from methanol gave 230 mg. of crystals having the following characteristics: M .P. l86-l89 C., [@1 +281 (dimethsulfoxide).

Analysis.-Calcd. for C H NO' S (percent): C, 45.94; H, 7.28; N, 5.95; S, 13.63. Found (percent): C, 45.85; H, 7.24; N, 6.28; CI, 0.

PART A-2b Methyl 6,7 (S)-aziridino-7-deoxy-u-thiolincosaminide Following the procedure of Example 1, Part A-l, substituting the methyl 7(S)'-chloro-7-dexoy-a-thiolincosaminide by methyl 7(R) -chloro-7-deoxy-a-thiolincosaminde, there is obtained methyl 6,7 (S)-am'ridino-7-deoxyu-thiolincosaminide.

VI (R) VII (S) PART B-2 Methyl 7(R)-mercapto 7-deoxy-a-thiolincosaminide VIII (R) 0 in HN I SMe VII(S) 7(R)-'mercapto-7-'deoxylincomycin hydrochloride H3 C Ha HS- H s z P HANH- HO O HO K vrmn V(R) OH OH SMe SMe On acylation with trans-1-methyl-4-n-propyl-L-proline as in Example 2, Part F-2, of the parent application, there is obtained 7 (R)-mercapto-7-deoxylincomycin hydrochloride having the same characteristics as thatproduced in Example 2, Part fF-Z of the parent application.

8 We claim: 1. A compound of the formula:

configuration.

7. The process for making a compound of the formula:

where R is alkyl of not more than 20 carbon atoms, cycloalkyl of from 3 to not more than 8 carbon atoms or aralkyl of not more than 12 carbon atoms which comprises heating a solution of a compound of the formula:

--Halo NHr- HO O

L. ii...

where Halo is chlorine, bromine, or iodine, in the presence of an acid acceptor for the hydrogen halide liberated in the reaction at a reactive temperature below that at which substantial decomposition would take place.

8. The process of claim 7 in which the acid acceptor is anhydrous sodium carbonate.

9. The process of making compounds of the formula:

NHz-

9 10 wherein R is alkyl of not more than 20 carbon atoms, 10. The process of claim 7 in which the product iscycloalkyl of 3 to not more than 8 carbon atoms, or heated in solution under pressure of hydrogen sulfide. aralkyl of not more than 12 carbon atoms which com- 11. The process of claim 8 in which the product is prises heating a solution of a compound of the formula: heated in solution under pressure of hydrogen sulfide.

5 References Cited HN\ 0H3 UNITED STATES PATENTS 1 3,380,992 4/1968 Argoudelis et a1. 260-210 R l 10 3,459,734 8/1969 Magerlein 260-210 R if lg LEWIS GOTTS, Primary Examiner OH I. R. BROWN, Assistant Examiner under pressure of hydrogen sulfide at a reaction tempera- 15 US Cl.

ture below that at which substantial decomposition would take place. 2609 R. 999

UNITED STATES PATENT OFFICE ERTIF ICATE OF QQRREQTIGN Patent No. 3 689 74 Dated September 5, 1972 Inventor(s) Fre'd Kagan and Barney J. Mager lein It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, I ine 11, for "mu ic" read mucic 1 ine 11 for "'amphor i c" readcam phoric .1 ine 16, for 'benze'nsul I onic" read benzenesul i onic Column 5, 1 ine 5 9, For

"7(R)" read 7(5) Column 6, I ine 23, for "St re tococcus Faecal is read Staghylococcus aureus Column 7, I ine 15, fo. "(d imethsul fox'ide) i read (d imethy 1 SUI foxide) Signed and Sealed this 8th day of May 1973.

ram mt -St wwmn YPLFLETCIAI-ERJB. ROBERT GOTTSCHALK .A'ttosting Officer a v ComImLssioner of Patents uscomwoc sows-ps9 U,S. GOVERNMENY 

